Rails - 使用 2 个模型按日期范围过滤答案

【问题标题】：Rails - filter by date range with 2 modelsRails - 使用 2 个模型按日期范围过滤
【发布时间】：2020-04-04 17:55:27
【问题描述】：

我有两种模式：空间和预订。 Space has_many bookings 并且 Booking 有两个日期属性：check_in 和 check_out。

给定一个有效的日期范围，我想显示此范围内的所有可用空间

这是视图：

        <%= form_tag spaces_path, method: :get do %>
        <%= date_field_tag :query1,
        params[:query1],
        class: "form-control" %>
        <%= date_field_tag :query2,
        params[:query2],
        class: "form-control" %>
        <%= submit_tag "Search", class: "btn" %>
        <% end %>

这是空间控制器：

(...)
def index
    if params[:query1].present? && params[:query2].present?
      query1 = DateTime.parse(params[:query1])
      query2 = DateTime.parse(params[:query2])
      search = query1..query2

      bookings = Booking.all

      # returns the bookings that overlaps with the search
      overlapping_bookings = bookings.select do |booking|
        check_in = booking[:check_in]
        check_out = booking[:check_out]
        period = check_in..check_out
        search.overlaps?(booking.period)
      end

      # returns the spaces_id of the bookings that overlaps
      overlapping_space_ids = overlapping_bookings.select do |overlapping_booking|
        overlapping_booking[:space_id]
      end

      # remove the duplicates
      overlapping_space_ids.uniq!

      # remove the spaces with bookings that overlap with the search
      @spaces = Space.all.reject do |space|
        overlapping_space_ids.include? space[:id]
      end
    else
      @spaces = Space.all
    end
  end
(...)

我认为我的问题的根本原因是我将Active Record Query Object 视为哈希数组，不确定它是否正确。我对此进行了一些研究，但没有找到任何详尽的答案。

【问题讨论】：

标签： ruby-on-rails ruby rails-activerecord

【解决方案1】：

使用 SQL 子查询（例如在 PostgreSQL 中）您可以这样做：

sql = <<SQL
SELECT *
FROM spaces
WHERE id in (
  SELECT space_id
    FROM bookings
   WHERE 
    (check_in, check_out) OVERLAPS (:from, :to)
  )
SQL;

Booking.find_by_sql([sql, {from: query1, to: query2})

希望有帮助:)

【讨论】：

【解决方案2】：

我会先为Booking 模型添加一个作用域：

# in app/models/booking.rb
scope :overlapping, ->(from, to) {
  where(
    "(check_in, check_out) OVERLAPS (?, ?)", from, to
  )
}

然后将整个控制器方法更改为：

def index
  @spaces = Space.all

  if params[:query1].present? && params[:query2].present?
    from = DateTime.parse(params[:query1])
    to   = DateTime.parse(params[:query2])

    @space = @space.where.not(
      id: Booking.select(:space_id).overlapping(from, to)
    )
  end
end

【讨论】：